#include<iostream>
using namespace std;
int main()
{
    int m;//1~100
    int t;//1~100
    int s;//1~10000
    cin >> m >> t >> s;
    if (t == 0)
    {
        cout << "0" << endl;
    }
    else if ((m - ((s + t - 1) / t)) > 0)
    {
        cout << m - ((s + t - 1) / t) << endl;
    }
    else
    {
        cout << "0" << endl;
    }
    return 0;
}